A chip-type multilayer ceramic capacitor is one of typical multilayer ceramic electronic components. With miniaturization and sophistication of electronic devices in recent years, there is more demand than ever before for small-size and large-capacity multilayer ceramic capacitors having a large electrostatic capacity per unit volume.
To realize small-size and large-capacity multilayer ceramic capacitors, it is generally required not only to reduce the thicknesses of ceramic layers and inner electrode layers, but also to increase the number of ceramic layers and inner electrode layers of a multilayer portion, that is, to achieve further multilayering.
However, the multilayering increases the ratio of inner electrode layers per unit volume of the multilayer ceramic capacitor. As a result, a difference in sintering shrinkage temperature between the ceramic layers and the inner electrode layers leads to an increased occurrence of delamination.
Moreover, a ceramic material forming the ceramic layers and a metal forming the inner electrode layer portion have different thermal expansion coefficients. This means that in a multilayer ceramic capacitor obtained through a sintering process, there is internal stress caused by the difference in thermal expansion coefficient. The internal stress increases as the ratio of inner electrode layers is increased by the multilayering described above. This may cause cracks to occur in response to thermal shock.
As a solution to the problems described above, a multilayer ceramic electronic component illustrated in FIGS. 8 and 9 has been proposed (see Patent Document 1). As illustrated, the multilayer ceramic electronic component includes a multilayer body 103 having ceramic layers 107 and inner electrode layers 105 and 106 alternately stacked, and outer electrodes 102 and 102 disposed on respective end portions of the multilayer body 103 and connected to the inner electrode layers 105 and 106. The inner electrode layers 105 and 106 contain first ceramic particles (not shown) having an average particle diameter less than or equal to an average particle diameter of conductor particles, and second ceramic particles 108 (see FIG. 9) having an average particle diameter greater than the thickness of the inner electrode layers 105 and 106.
Patent Document 1 states that since the invention disclosed in Patent Document 1 reduces the difference in thermal expansion coefficient between ceramic layers 107 and enhances bonding strength between them, it is possible to obtain a multilayer ceramic electronic component which is resistant to cracks and delamination in the multilayer body 103 because of its high resistance to thermal stress caused by, for example, heat shock that occurs when the multilayer ceramic electronic component is mounted on a circuit board and the outer electrodes 102 and 102 are soldered (see paragraph 0045 in Patent Document 1).
However, in the multilayer ceramic electronic component disclosed in Patent Document 1, the presence of the second ceramic particles having an average particle diameter greater than the thickness of the inner electrode layers 105 and 106 causes breaks in the inner electrode layers. If the multilayer ceramic electronic component is a multilayer ceramic capacitor, this leads to degradation of electrostatic capacity and failure to meet the demand for increased capacity.
A similar problem also applies to multilayer ceramic electronic components other than multilayer ceramic capacitors.
Patent Document 1: Japanese Unexamined Patent Application Publication No. 2000-277369